Liquid Level Sensor Using Rotating Float and Magnetoresistive Detection

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Solution Overview

Problem

Existing liquid level detection methods face challenges in precision, with magnetoresistive element-based sensors experiencing poor accuracy and magnetic float getting stuck due to fixed direction requirements, leading to high costs and processing difficulties.

Innovation Solution

A liquid level detection method using two magnets with same poles facing each other, equidistantly disposed magnetoresistive elements, and a float that rotates within an electronic tube, allowing for continuous, high-precision measurement by detecting changes in magnetic field intensity between adjacent magnetoresistive elements, eliminating the need for a guide rail and reducing the risk of float sticking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of magnetoresistive elements is increased to improve detection precision, then measurement precision is improved, but manufacturing cost and processing difficulty increase

Engineering Contradiction:
Improveliquid level detection precisionVSAvoidnumber of magnetoresistive elements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the functions of multiple magnetoresistive elements into a single integrated magnetoresistive component. This single component performs the detection function that would otherwise require multiple discrete elements, thereby reducing device complexity and manufacturing cost while maintaining the necessary measurement precision through its design configuration

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single magnetoresistive component is designed to perform multiple detection functions simultaneously. It can detect magnetic field changes from different positions and provide comprehensive liquid level measurement data, replacing what would traditionally require multiple specialized elements working in parallel

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a guide rail-recess structure is used to ensure fixed direction movement of the magnetic float, then measurement reliability is improved, but the float may get stuck and productivity decreases

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidcontinuous operation capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent transitions from a static guide rail-recess structure to a dynamic detection system. The magnetic float is no longer constrained to move in a fixed direction along a guide rail, but can move freely while being detected by the magnetoresistive component. This dynamic approach eliminates mechanical constraints that cause sticking while maintaining measurement reliability through magnetic field detection

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent replaces the mechanical guide rail-recess constraint system with a magnetic field-based detection system. Instead of using mechanical structures to enforce fixed direction movement, the system uses magnetic field interactions to track the float's position, thereby eliminating mechanical friction and sticking problems while maintaining measurement accuracy

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method achieves high measurement precision, simplifies the detection process, reduces manufacturing costs, and prevents float sticking, enabling continuous and accurate liquid level monitoring without the need for excessive magnetoresistive element placement or fixed float direction.

Implementation Method 1

disposing a plurality of magnetoresistive elements equidistantly for collecting magnetoresistive signals at a movement range of the float

Methodology Applied
Scientific EffectMagnetoresistive effect: Magnetoresistance

Data Source

PatentEP3499196B1Liquid level detection method and liquid level sensor
Publication Date: 2021.07.14 DONG GUAN ZHENGYANG ELECTRONIC MECHANICAL LTD
  • EP3499196B1 patent drawingFigure 1
  • EP3499196B1 patent drawingFigure 2
  • EP3499196B1 patent drawingFigure 3~4

AI summary

A liquid level detection method and a liquid level sensor, related to the technical field of liquid level measurement. The liquid level detection method comprises: when the position of a buoy (3) changes, a magnetic field formed by two magnetic stones (4) arranged with a same pole opposite each other also changes position with the buoy (3); multiple magnetoresistive elements (2) used for collecting a magnetoresistive signal are equidistantly provided in a range of movement of the buoy (3), when the buoy (3) moves, adjacent two magnetoresistive elements (2) arranged between the two magnetic stones (4) detect a change in the intensity of the magnetic field and output a linear detection result; and a liquid level height is produced by calculating on the basis of the detection result.